Little Polly Always Clever

Little Polly, always clever,
Takes a leaf of live-forever;
Before you know it
You see her blow it,
A gossamer sack
With a velvet back.
How big it grows
As she puffs and blows!
But have a care,
It is full of air.
Ere Polly will stop
It'll crack with a pop;
And that's the end of the live-forever;
But little Polly is very clever.